Work-feeding mechanism.



H. A. GRIFFITHS.

WORK FEEDING MECHANISM.

APPLICATION FILED MAR. 24. 1915.

1 1mm. P11161111 Dec.14,1915.

2 SHEETS-SHEET 1.

COLUMBIA PLANDGRAPH co.. WASHINGTON. 01c,

H. A. GRIFFITHS.

WORK FEEDING MECHANISM.

APPLICATION FILED MAR. 24. 19].).

2 SHEETS-SHEET 2.

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Patented DEG-14,1915.

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HARRY ALBERT GRIFFITHS, OF EDGBASTON, BIRMINGHAM, ENGLAND.

WORK-FEEDING MECHANISM.

To all whom itmag concern Be it known that I, HARRY ALBERT GRIF- rrrrrs, subject of the King of Great Britain, residing at 22 Francis road, Fdgbaston, in the city of Birmingham, England, have invented certain new and useful Improvements Relating to Work-Feeding Mechanism, of which the following is a specification.

This invention relates to cutting, drawing and like presses for operating on metal and other sheets, and, more especially, to those presses which are employed for cutting out from thin metal sheet the blanks-employed in the manufacture of small metal boxes and other articles. Such presses are ordinarily provided with two slides at right angles to each other, to one of which the metal sheet is secured. By means of one of the slides the sheet is moved progressively across the tools, and when one row of blanks has been cut out the other slide advances the sheet toward the tools and brings the next row into position. The first slide then feeds the sheet across the tools in the reverse direction to the first. By such movements across the tools and toward the tools successive rows of blanks are removed from the sheet until as much as possible of the sheet has been utilized.

The present invention has for its object to provide improved, means for automatically feeding the sheets across the cutting tools.

The invention comprises the combination with a slide, of a pair of racks, and a pawl and stop in conjunction with each rack, the arrangement being such that while the intermittent movements of the slide are being produced in one direction by the action of one of the pawls on oneof the racks, the stop in conjunction with the other rack is operating to bring the slide to rest in the correct position at the end of each of such movements. y Y

Referring to the two accompanying sheets of explanatory drawings Figure 1 is a plan, Fig. 2 an end elevation and Fig. 3 a front elevation of feed mechanism constructed in accordancewith this invention. Figs. 4 and 5 are respectively plan and front elevation to a larger scale than Figs. 1 to 3' of one part of the feed mechanism, the complete mechanism comprising mainly two of such parts. i

, In the construction of feed mechanism as Specification of Letters Patent.

illustrated, a slide a which produces the intermittent movements of the sheet across the cutting tools is mounted upon a suitable guide Z). The slide which produces the movements of the sheet toward the tools at the end of each complete traverse of the slide a is mounted on the latter and is indicated by 2. The cutting tools are shown diagrammatically and indicated by 3. It will be understood that the slide a and its associated mechanism are mounted on the frame 4 of the machine in any convenient position relative to the cutting tools. The slide a has secured to it a pair of parallel rack bars 0 which are adapted to be engaged by oppositely disposed pawls cl. The pawls engage notches c in the bars, which notches are shaped as shown and arranged at equal distances. All the notches of one bar face in the opposite direction to those of the other bar. The pitch or distance between the centers of the notches corresponds to the pitch of the blanks to be cut from the sheet, or the distance the slide is moved at each operation. One pawl produces the intermittent movementsof the slide in one direction and the other pawl the corresponding movements in the opposite direction. Each pawl is mounted upon an adjustable block fsecured to a reciprocatory bar 9 carried in guides or brackets h on the framing of the machine, and the two bars are reciprocated in opposite directions. Asshown in the drawings the bars a and 7 and the pawls are mounted on opposite sides of the slide. Adjacent to each rack bar is mounted a bellcrank lever t which is pivoted on a bracket j attached to the machine frame. Upon the lever i is carried 'a stop is capable not only of a rocking movement with the lever but also of a sliding movement relative to the Patented Dec. ML, 1915. Application filed March 24, 1915. Serial No. 16,651 i lever. The stop is situated immediately above the rack bar so that it can engage the teeth in the said bar. Its movement relative to the bell-crank lever is regulated by a blade or other spring t" at tached to the lever and bearing against one end or other convenient part of the stop.

In conjunction with the lower end of each stop is arranged a lever Z and buffer spring Z for the purpose hereinafter described.

through a lateral projection or shoulder g on the stop.

In operation the approximate adjustment is effected by the pawl acting on the one notched rack bar 0, and the final adjustment by the stop engaging the other bar. It will be understood, therefore, that to control the movements of the slide in one directionthe pawl of the set of mechanism on one side of the slide and the stop of the set of mechanism on-the other side of the slide are employed. The other stop and pawlare out of action, and are brought into use to produce the opposite movements of the slide when the first mentioned pawl and stop are out of action. In Fig. 3 the pawl and stop mechanism on the far side of the slide only is shown and the portion of the guide and the rack bar at the front of the slide are shown as broken away for clearness of illustration. The pawl which operates whenthe particular stop illustrated is in use is shown in dotted lines .as is also the notch which it engages. The operative pawl and the notch it engages are likewise shown in dotted lines in Fig. 5. It will be understood that the dotted pawls and notches belong to the mechanism on the near side of the slide.

In Fig. 2' the stop mechanism on both sides of the slide is omitted to avoid confusion.

' The major portion of each movement of the slide is produced by the pawl which engages one of the rack bars and is advanced to the required extent by the reciprocatory bar on which the pawl is mounted. When the mo ements are performed rapidly cons derable difficulty is experienced owing to the momentum of the slide and the parts associated therewith. and in consequence when rapid operation is required it is impossible to'accuratelv move the slide from one posit on to the next b means of the pawl only. l 'sually the awl is set to move through a distance slightl less than the mo ement re ouired in the slide. overmmninc of the slide being relied upon to make up thedefic ency and carry the slide to the proper position. Durinr. the mo ement of the pawl (Z while in enca ement with its rack bar c the sto 71: adjacent to the other bar 0 slides ve tically in o eng ement with a notch .6 under the ac ion o f'its spring 2"". Afte the pawl has finish-ed its 'mo 'ement he sl de a is ar ested b the ensra cement of the stop k with :the one end of "the potoh :e which it engaees in the ot e lh'a c. The momentum is ab o bed and shock a oid-ed :lor the rocking lot the stop with its lever '2' about the pi ot of the latter. sucih mo ement being transmitted by the stop to the butter lever .Z and thesnring Z".- Due to the compression of the louder the slide a brought to rest gentlv. The

' strength of the sprin is ad-imsted so that it b-nines *the s ide to rest exactly in the right position. the pawl d ead its reciprocatory bar 9 is returning the other reciprocatory bar 9 adjacent to the stop is is movmg in the opposite direction, and during Such movement the cam bar p which is socured to and moves with the said bar 9 lifts the stop out of engagement with the rack bar 0. The bar 9 then continues its movement idly. Meanwhile the bar carrying the operative pawl is approaching its initial position, and when this is reached the above described cyclev of operations is repeated. By arranging for approximate movements to be produced by the pawl and the fine adj ustments to the proper positions by the stop higher speed of operation is obtainable than with feeding mechanism heretofore employed. To prevent any possibility of recoil of the slide by the spring Z, a bar 5 is fixed longitudinally on the guide Z) and arranged alongside the slide a. A vulcanized fiber or like bearing surface (3 is provided on the side of the slide adjacent to the bar and the latter is pressed against such surface by a pressure piece 7 carried by the slide and controlled by springs 8. The friction between vthe slide and the bar 5 acts as a brake and effectively prevents recoil of the slide after it has been brought to rest by the spring Z as above described.

The reciprocation of the bars carrying the pawls is effected by a pair of levers r mounted on parallel shafts If which are connected by toothed wheels u, one of the shafts being rocked from any convenient part of the press mechanism, so that each cutting stroke of the tools is followed by an opertionof the slide. For putting the pawls into and out of action alternately a pair of bars 0 are mounted parallel with the slide and provided with levcr-like projections w for engaging the pawls. The two bars are connected by levers a; and a link 1 at one end and arranged in conjunction with any convenient throw-over mechanism which is actuated when the slide reaches the ends of its movements. At the completion of the intermittent movements of the slide in one direction the bars 4) are rocked to put the operative pawl out of action and the inoperative pawl into action. The slide then traverses intermittently in the opposite direction. and when it reaches the .end of this series of movements the action of the pawls is reversed.

The invention is not limited to the .constr ctional or mechanical details herein described. as these may be varied to meet difi erent reou-irements. \Vhere adiustability is required in the arious parts of the mechanism any convenient provision is made gas shown.

iHavingthus described my invention what 1 claim as new and'desire to secure by Letters Patent is r 1. [11 cutting, drawing and like presses for operating on metal and other sheets, means for feeding the sheets comprising, a slide, a pair of oppositely notched racks attached to the slide, a reciprocatory bar and a pawl carried by such bar in conjunction with each rack, also a sliding stop in conjunction with each rack, a lever carrying the stop, a spring bufi'er abutting against the stop, and means attached to the reciprocatory bar whereby the stop is intermittently withdrawn from the rack, substantially as described.

2. In cutting, drawing and like presses for operating on metal and other sheets, means for feeding the sheets comprising, a slide, a pair of oppositely notched racks attached to the slide, a reciprocatory bar mounted parallel with each rack, a pawl and a stop actuating device on each bar, means whereby opposite recipro-catory movements are imparted to the bars, a sliding stop in conjunction with each rack, a lever carrying the stop, a buffer lever abutting at one end against the stop, a spring acting on the other end of the bufler lever, and a spring acting on the stop, substantially as described.

3. In cutting, drawing and like presses for operating on metal and other sheets, means for feeding the sheets comprising, a slide, a pair of oppositely notched racks attached to the slide, a reciprocatory bar mounted parallel with each rack, a block attached to each bar, a pawl and a notched stop actuating bar carried by the said block, interconnected shafts and levers imparting opposite reciprocatory movements to the bars, a sliding stop arranged in conjunction with each rack and adapted to cooperate with the stop actuating bar, a lever carrying the stop, a buffer lever abutting at one end against the stop, a spring acting on the other end of the buffer lever, a spring acting on the stop, levers and interconnected bars whereby one of the pawls is brought into action and the other put out of action at theend of each complete traverse of the slide, and a brake bar in conjunction with the slide, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HARRY ALBERT GRIFFITHS.

Witnesses:

EDWARD MARKS, JOHN MORGAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

